> ## Documentation Index
> Fetch the complete documentation index at: https://upstash-vector.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Publish Messages

Publishing a message is as easy as sending a HTTP request to the `/publish`
endpoint. All you need is a valid url of your destination.

<Frame>
  <img src="https://mintlify.s3-us-west-1.amazonaws.com/upstash-vector/img/qstash/publish.png" width="688" />
</Frame>

<Info>
  Destination URLs must always include the protocol (`http://` or `https://`)
</Info>

## The message

The message you want to send is passed in the request body. Upstash does not
use, parse, or validate the body, so you can send any kind of data you want. We
suggest you add a `Content-Type` header to your request to make sure your
destination API knows what kind of data you are sending.

## Sending custom HTTP headers

In addition to sending the message itself, you can also forward HTTP headers.
Simply add them prefixed with `Upstash-Forward-` and we will include them in the
message.

#### Here's an example

```
curl -XPOST \
    -H 'Authorization: Bearer XXX' \
    -H 'Upstash-Forward-My-Header: my-value' \
    -H "Content-type: application/json" \
    -d '{ "hello": "world" }' \
    'https://qstash.upstash.io/v2/publish/https://example.com'
```

In this case, we would deliver a `POST` request to `https://example.com` with
the following body and headers:

```json
// body
{ "hello": "world" }

// headers
My-Header:      my-value
Content-Type:   application/json
```

#### What happens after publishing?

When you publish a message, it will be durably stored in an
[Upstash Redis database](https://upstash.com/redis). Then we try to deliver the
message to your chosen destination API. If your API is down or does not respond
with a success status code (200-299), the message will be retried and delivered
when it comes back online. You do not need to worry about retrying messages or
ensuring that they are delivered.

## Publish to topic

Topics allow you to publish a single message to more than one API endpoints. To
learn more about topics , check [topics section](/qstash/features/topics).

Publishing to a topic is very similar to publishing to a single destination. All
you need to do is replace the `URL` in the `/publish` endpoint with the topic
name.

```
https://qstash.upstash.io/v2/publish/https://example.com
https://qstash.upstash.io/v2/publish/my-topic
```

```
curl -XPOST \
    -H 'Authorization: Bearer XXX' \
    -H "Content-type: application/json" \
    -d '{ "hello": "world" }' \
    'https://qstash.upstash.io/v2/publish/my-topic'
```

## Optional parameters and configuration

QStash supports a number of optional parameters and configuration that you can
use to customize the delivery of your message. All configuration is done using
HTTP headers.